924Board.org

Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

I installed my rear 30mm torsion bars yesterday, i put the bars a few teath lower. But having the car back on the wheels is is even higher then before. Ofcourse this is because the bars are much stiffer.

Does any one know about how much 1 teeth (inside or outside) will lower the car with the 30mm bars ?
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937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

morghen · Joined: 21 Jan 2005 Posts: 9095 Location: Romania

you'll have to give it a few more tries...you can never get it right from the first try even if you know how much the teeth raise/lower it...well unless you get lucky.

right click, save as: http://www.924board.org/downloads/Torsionbarsetup.doc
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gegge · Joined: 27 Jul 2007 Posts: 1124 Location: Sweden

One tooth is equal to 360/40 or 360/44 depending on inside or outside.

IIRC the orginal setup fro 924 was 19 degrees and 968cs got 8 degrees with 25,5 mm torsion bars? Correct answer was:

All 968 CS 14.0 deg
All 968 CS M030 9.0 deg
USA Coupe 18.5 deg
USA M030 14.0 deg
Stock 951S 18.0 deg

Let´s say that the car weight is 2640 lbs, 660lbs on one rear wheel:
23,5mm bars equals 126lbs/inch = compression of 5,2inch
30,0mm bars equals 334lbs/inch = compression of 2,0inch

So we have to compensate for the lost 3,2 inch. How long are the tailing arms? 16inch? Then arcsin(3,2/16)=11,5 degrees.

I would guess that close to horizontal level is right if you want to lower the car 2inch or to get close to 968 ride height.

Let me know what the result is, because I have to do the exact same thing since I choosed 30mm as well.
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Carl Fredrik Torkildsen

924 turbo -81 Carrera GT RESTOMOD
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924RACR · Posted: Sun Jan 25, 2009 11:57 pm Post subject:

Yeah, you have to move it a lot - the 30's don't move much when you put the car down. When I switched over, I had to try a couple of times before I got it right.

Make sure you also have the spring plate height adjustment at the same point on both sides; if you don't, you can end up having the two sides at different indexing on the t-bars, which can be a real PITA later on when you're trying to balance the car.

Definitely use a protractor or angle finder/gauge to get both sides set the same.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

There is a very detailed article on Clark's Garage about this.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

I use the car mostly for trackdays and some times on the normal road.

What would be the right hight ?

Measured now:

After the front wheel is now: 5,5 inch
Before the rear wheel is now: 6,7 inch

The guys who race a 944 say the the rear should be lower then the front.

_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

The right height on a 924 is LEVEL.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

924RACR · Posted: Mon Jan 26, 2009 2:55 am Post subject:

Yes, definitely. Certainly, it's possible to run a 924/944 nose-high - I have - but not preferred.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

If you don't feel like another round of dissassembly, you have a great excuse to get a coilover sleeve kit with adjustable spring perches. They are ungoldy cheap, IMO, for what they can accomplish.

Example HERE.

And FWIW you may be better off using a level in the door sill instead of trying to measure points on the body.
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Cedric · Joined: 27 Aug 2004 Posts: 2809 Location: Sweden

Try this excel sheet. It might help:

http://944spec.org/944SPEC/content/view/42/25/
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Dutch924-racer · Joined: 23 Jul 2007 Posts: 1081 Location: The Netherlands

Second try was just perfect, I will post pictures later

thanks guys !
_________________
937 trackday car
Series 2 engine
951S turbo and intercooler
Fast road camshaft
Forge recirculation valve + boost controller